Automatic inflatable dinghies



Dec. 26, 1967 B. R. A. REFFELL ET AL 3,359,579

AUTOMATIC INFLATABLE DINGHIES Filed Jan. 6, 1966 BRIAN RA. EEFFELL Mo SIDNEY MITCHELL Ewe/v2) By M United States Patent 3,359,579 AUTOMATIC INFLATABLE DINGHIES Brian R. A. Relfell, Middlesex, and Sidney Mitchell,

Surrey, England, assignors to The Walter Kidde Company Limited, Middlesex, England, a British company Filed Jan. 6, 1966, Ser. No. 519,175 Claims priority, application Great Britain, Jan. 11, 1965, 1,243/ 65 2 Claims. (Cl. 9-11) ABSTRACT OF THE DISCLOSURE An automatic inflatable dinghy of the invention comprises a peripheral buoyancy tube containing an internal high pressure tube which is attached to the outer surface thereof. This high pressure tube has a connection at one end to a source of air under high pressure and a pair of orifices at opposite ends of a transverse plane of the dinghy so that after the high pressure tube has been inflated air will pass through these orifices into the buoyancy tube.

The invention relates to inflatable dinghies of the kind which are carried in a deflated condition, as a personal pack by airmen, or others, and which are capable of automatic deployment under the person of the carrier, when inflation is started.

In British Patent No. 891,300 there is described a dinghy in which a small diameter high pressure tube is secured to the periphery of the buoyancy tube for the purpose of unfolding the dinghy from a folded condition, when the small diameter tube is inflated to a high pressure in relation to the final pressure in the buoyancy tube. In the known arrangement the small diameter high pressure tube has an inlet opening for high pressure gas and a connection to the buoyancy tube at the other end so that a substantial pressure is built up in the high pressure tube before any appreciable volume of gas passes from the other end of the tube into the buoyancy tube. The resistance to flow in the small diameter tube is achieved by a careful selection of the tube diameter, or by the use of a restrictor at the outlet end of the tube.

It has been found in practice that although the above arrangement provides for a rapid unfolding and deployment of the dinghy, the subsequent inflation of the buoyancy tube from a single outlet point is not sufficiently uniform to ensure that the dinghy will always in flate so that the survivor to whom it is secured will remain inside and above the dinghy. In order to overcome this difliculty it has also been proposed to use one gas storage means for inflation of a small diameter high pressure tube, which does not communicate with the buoyancy tube and two separate gas storage means to inflate the buoyancy tube, the further gas storage means being respectively connected to the buoyancy tube on opposite sides of the dinghy. However this increase in bulk causes difficulties in endeavouring to reduce the size of the dinghy pack as is necessary for aircraft use.

The object of the present invention is to provide a dinghy of the aforesaid kind, which is small in the de flated condition and in which the inflation of the buoyancy tube of the dinghy after its deployment can be effected in a uniform and simplified manner.

According to the invention there is provided an inflatable dinghy having a peripheral buoyancy tube and secured thereto an additional tube of relatively small diameter and capable of withstanding high gas pressure so as to straighten out and unfold the dinghy when a high gas pressure is built up therein, characterised in that said additional tube is provided with two orifices of sub- 3,359,579 Patented Dec. 26, 1967 stantially equal size located in the same transverse plane on opposite sides of the dinghy, for permitting gas to pass into and to inflate simultaneously both sides of the buoyancy tube after pressure has built up in the said additional tube.

According to a feature of the invention said additional tube may be connected to a high pressure gas storage at a point located substantially mid-way between said two orifices, so that during the inflation of the dinghy the streams of gas through the two orifices are balanced.

One embodiment of the invention will now be described, by way of example, with reference to the accompanying drawing which shows an inflated dinghy in plan with parts shown in section.

Referring now to the drawing, the dinghy 10 comprises a large peripheral buoyancy tube 11 to which is attached a flexible floor 12. Within the buoyancy tube 11 and secured to the inside surface thereof at its outer periphery is an endless additional high pressure tube 14. The high pressure tube 14 is about twelve feet long, approximately two and a half inches in diameter, has an internal volume of about two hundred and forty cubic inches and is capable of withstanding an internal pressure of the order of seventy to one hundred pounds per square inch. The buoyancy tube 11 has an internal capacity of the order of eight thousand six hundred and forty cubic inches and is normally inflated to about two pounds per square inch.

The buoyancy tube 11 has a smaller diameter at the narrow foot or stern end 15 of the dinghy and is of enlarged diameter at the pointed Wide body or how end 16."The buoyancy tube 11 carries a high pressure gas bottle 17 at the stern end. This gas bottle 17 is connected to the high pressure tube 14 at about the mid-point of this end.

At opposite sides of the dinghy 10 in a transverse zone thereof such as would lie between the hips and knees of an occupant, the high pressure tube 14 is provided with two equal sized orifices 18 and 19 of about a quarter of an inch in diameter. In use the discharge of gas into the high pressure tube 14 at one end of the dinghy 10 causes a rapid build up of pressure in the said high pressure tube 14 which straightens out and unfolds the dinghy 10. Gas leaks through the orifices 1 8 and 19 during inflation of the high pressure tube 14 but it will be appreciated that the gas pressure build up in the high pressure tube 14 will be greater than the loss due to leakage. As soon as the high pressure tube 14 is fully inflated (usually to about seventy-two pounds per square inch), the pressure in the additional high pressure tube 14 causes gas to flow rapidly through the orifices 18 and 19 (at about one third of a cubic foot per second through each orifice), thus inflating both sides of the buoyancy tube 11 simultaneously. If desired, the additional high pressure tube 14 may be provided on each opposite side of the dinghy 10 with more than one orifice, but the arrangement should be such that the orifices in the high pressure tube on one side of the dinghy balance those on the other side.

The buoyancy tube is provided with two baflies 21 located on either side of the dinghy in a transverse plane thereof between the hips and shoulders: of the occupant. These baflles which are provided with bleed holes to enable gas to penetrate to the space between them, ensure that the initial inflation of the buoyancy tube occurs in the region of both of the discharge orifices simultaneously.

In some conditions of use the buoyancy tube after its deployment, but before its inflation, may be subjected to greater water pressure on one side of the dinghy than on the other. For example, owing to the position of the survivor, one side of the dinghy may be below the surface of the water whilst the opposite side may be on the surface. This difference in water pressure may have the effect of causing the gas discharged through both orifices in the additional tube, to be directed first to one side of the dinghy with the result that the dinghy tilts during inflation and overturns with the survivor strapped beneath it. In order to reduce the possibility of unbalanced inflation the buoyancy tube may have the baffles located on the fore and aft axis of the dinghy preferably at the foot end of the dinghy, so that gas discharged from the two orifices cannot flow rapidly to the same part of the buoyancy tube.

The high pressure tube may be constructed from thin flexible fabric, for example, a rubberised woven nylon, which can be readily folded with the dinghy and which being of small bulk, permits the dinghy to be stowed in a very confined space. The thinness of the fabric of the high pressure tube enables the tube to be made of rather larger diameter tube than has been hitherto proposed and as a consequence it straightens out at a lower pressure than would be the case with a tube of smaller diameter.

Under certain circumstances it may be desirable for each orifice to be covered with a porous fabric patch of suitable material, for example, unproofed woven nylon. Typically the patch may be made of the same material as the high pressure tube, differing therefrom in that it is unproofed. These patches in addition to providing a difliused flow of gas to the buoyancy tube, reinforce the edges of the orifices and prevent the edges from tearing.

Alternatively, if desired, under certain circumstances each orifice may be fitted with a pressure relief valve, to serve as a restrictor and to prevent any gas escaping to the buoyancy tube during the build up of pressure in the additional tube.

We claim:

1. An inflatable dinghy having sides and ends and comprising:

4 (a) a peripheral buoyancy tube extending around the dinghy, (b) a continuous additional tube of relatively small diameter and capable of withstanding high gas pres- 5 sure, the said additional tube being connected to the outer circumference of the buoyancy tube so that on being inflated, the said additional tube straightens out and unfolds the buoyancy tube, said additional tube having a pair of orifices connecting the said tubes, which said orifices are of substantially equal size and are located at the sides of the dinghy in the same transverse plane of said dinghy, and (c) inflating means connected to the said additional 15 tube midway between the said orifices.

2. A dinghy as claimed in claim 1 further comprising a pair of bafi'les within the buoyancy tube between the said orifices on the sides thereof remote from the said 20 source of high pressure.

References Cited UNITED STATES PATENTS 2,580,639 1/1952 Baker 9316 X 2,993,217 7/1961 SWitlik 9-316 3,080,582 3/1963 Reifell 92 FOREIGN PATENTS 30 891,300 3/1962 Great Britain.

FERGUS S. MIDDLETON, Primary Examiner.

MILTON BUCHLER, Examiner.

R. A. DORNON, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,359,579 December 26, 1967 Brian R. A. Reffell et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below In the heading to the printed specification, lines 4 and 5, for "The Walter Kidde Company Limited, Middlesex, England, a British company" read The Walter Kidde Company Limited, Middlesex, England, a British company, and R. F. D. Company Limited, Surrey, England, a British company Signed and sealed this 15th day of April 1969.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer 

1. AN INFLATABLE DINGHY HAVING SIDES AND ENDS AND COMPRISING: (A) A PERIPHERAL BUOYANCY AND TUBE EXTENDING AROUND THE DINGHY, (B) A CONTINUOUS ADDITIONAL TUBE OF RELATIVELY SMALL DIAMETER AND CAPABLE OF WITHSTANDING HIGH GAS PRESSURE, THE SAID ADDITIONAL TUBE BEING CONNECTED TO THE OUTER CIRCUMFERENCE OF THE BUOYANCY TUBE SO THAT ON BEING INFLATED, THE SAID ADDITIONAL TUBE STRAIGHTENS OUT AND UNFOLDS THE BUOYANCY TUBE, SAID ADDITIONAL TUBE HAVING A PAIR OF ORIFICES CONNECTING THE SAID TUBES, WHICH SAID ORIFICES ARE OF SUBSTANTIALLY EUAL SIZE AND ARE LOCATED AT THE SIDES OF THE DINGHY IN THE SAME TRANSVERSE PLANE OF SAID DINGHY, AND (C) INFLATING MEANS CONNECTED TO THE SAID ADDITIONAL TUBE MIDWAY BETWEEN THE SAID ORIFICES. 